diff options
Diffstat (limited to 'fs/erofs/super.c')
| -rw-r--r-- | fs/erofs/super.c | 615 |
1 files changed, 615 insertions, 0 deletions
diff --git a/fs/erofs/super.c b/fs/erofs/super.c new file mode 100644 index 000000000000..caf9a95173b0 --- /dev/null +++ b/fs/erofs/super.c @@ -0,0 +1,615 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Copyright (C) 2017-2018 HUAWEI, Inc. + * http://www.huawei.com/ + * Created by Gao Xiang <gaoxiang25@huawei.com> + */ +#include <linux/module.h> +#include <linux/buffer_head.h> +#include <linux/statfs.h> +#include <linux/parser.h> +#include <linux/seq_file.h> +#include "xattr.h" + +#define CREATE_TRACE_POINTS +#include <trace/events/erofs.h> + +static struct kmem_cache *erofs_inode_cachep __read_mostly; + +void _erofs_err(struct super_block *sb, const char *function, + const char *fmt, ...) +{ + struct va_format vaf; + va_list args; + + va_start(args, fmt); + + vaf.fmt = fmt; + vaf.va = &args; + + pr_err("(device %s): %s: %pV", sb->s_id, function, &vaf); + va_end(args); +} + +void _erofs_info(struct super_block *sb, const char *function, + const char *fmt, ...) +{ + struct va_format vaf; + va_list args; + + va_start(args, fmt); + + vaf.fmt = fmt; + vaf.va = &args; + + pr_info("(device %s): %pV", sb->s_id, &vaf); + va_end(args); +} + +static void erofs_inode_init_once(void *ptr) +{ + struct erofs_inode *vi = ptr; + + inode_init_once(&vi->vfs_inode); +} + +static struct inode *erofs_alloc_inode(struct super_block *sb) +{ + struct erofs_inode *vi = + kmem_cache_alloc(erofs_inode_cachep, GFP_KERNEL); + + if (!vi) + return NULL; + + /* zero out everything except vfs_inode */ + memset(vi, 0, offsetof(struct erofs_inode, vfs_inode)); + return &vi->vfs_inode; +} + +static void erofs_free_inode(struct inode *inode) +{ + struct erofs_inode *vi = EROFS_I(inode); + + /* be careful of RCU symlink path */ + if (inode->i_op == &erofs_fast_symlink_iops) + kfree(inode->i_link); + kfree(vi->xattr_shared_xattrs); + + kmem_cache_free(erofs_inode_cachep, vi); +} + +static bool check_layout_compatibility(struct super_block *sb, + struct erofs_super_block *dsb) +{ + const unsigned int feature = le32_to_cpu(dsb->feature_incompat); + + EROFS_SB(sb)->feature_incompat = feature; + + /* check if current kernel meets all mandatory requirements */ + if (feature & (~EROFS_ALL_FEATURE_INCOMPAT)) { + erofs_err(sb, + "unidentified incompatible feature %x, please upgrade kernel version", + feature & ~EROFS_ALL_FEATURE_INCOMPAT); + return false; + } + return true; +} + +static int erofs_read_superblock(struct super_block *sb) +{ + struct erofs_sb_info *sbi; + struct page *page; + struct erofs_super_block *dsb; + unsigned int blkszbits; + void *data; + int ret; + + page = read_mapping_page(sb->s_bdev->bd_inode->i_mapping, 0, NULL); + if (!page) { + erofs_err(sb, "cannot read erofs superblock"); + return -EIO; + } + + sbi = EROFS_SB(sb); + + data = kmap_atomic(page); + dsb = (struct erofs_super_block *)(data + EROFS_SUPER_OFFSET); + + ret = -EINVAL; + if (le32_to_cpu(dsb->magic) != EROFS_SUPER_MAGIC_V1) { + erofs_err(sb, "cannot find valid erofs superblock"); + goto out; + } + + blkszbits = dsb->blkszbits; + /* 9(512 bytes) + LOG_SECTORS_PER_BLOCK == LOG_BLOCK_SIZE */ + if (blkszbits != LOG_BLOCK_SIZE) { + erofs_err(sb, "blksize %u isn't supported on this platform", + 1 << blkszbits); + goto out; + } + + if (!check_layout_compatibility(sb, dsb)) + goto out; + + sbi->blocks = le32_to_cpu(dsb->blocks); + sbi->meta_blkaddr = le32_to_cpu(dsb->meta_blkaddr); +#ifdef CONFIG_EROFS_FS_XATTR + sbi->xattr_blkaddr = le32_to_cpu(dsb->xattr_blkaddr); +#endif + sbi->islotbits = ilog2(sizeof(struct erofs_inode_compact)); + sbi->root_nid = le16_to_cpu(dsb->root_nid); + sbi->inos = le64_to_cpu(dsb->inos); + + sbi->build_time = le64_to_cpu(dsb->build_time); + sbi->build_time_nsec = le32_to_cpu(dsb->build_time_nsec); + + memcpy(&sb->s_uuid, dsb->uuid, sizeof(dsb->uuid)); + + ret = strscpy(sbi->volume_name, dsb->volume_name, + sizeof(dsb->volume_name)); + if (ret < 0) { /* -E2BIG */ + erofs_err(sb, "bad volume name without NIL terminator"); + ret = -EFSCORRUPTED; + goto out; + } + ret = 0; +out: + kunmap_atomic(data); + put_page(page); + return ret; +} + +#ifdef CONFIG_EROFS_FS_ZIP +static int erofs_build_cache_strategy(struct super_block *sb, + substring_t *args) +{ + struct erofs_sb_info *sbi = EROFS_SB(sb); + const char *cs = match_strdup(args); + int err = 0; + + if (!cs) { + erofs_err(sb, "Not enough memory to store cache strategy"); + return -ENOMEM; + } + + if (!strcmp(cs, "disabled")) { + sbi->cache_strategy = EROFS_ZIP_CACHE_DISABLED; + } else if (!strcmp(cs, "readahead")) { + sbi->cache_strategy = EROFS_ZIP_CACHE_READAHEAD; + } else if (!strcmp(cs, "readaround")) { + sbi->cache_strategy = EROFS_ZIP_CACHE_READAROUND; + } else { + erofs_err(sb, "Unrecognized cache strategy \"%s\"", cs); + err = -EINVAL; + } + kfree(cs); + return err; +} +#else +static int erofs_build_cache_strategy(struct super_block *sb, + substring_t *args) +{ + erofs_info(sb, "EROFS compression is disabled, so cache strategy is ignored"); + return 0; +} +#endif + +/* set up default EROFS parameters */ +static void erofs_default_options(struct erofs_sb_info *sbi) +{ +#ifdef CONFIG_EROFS_FS_ZIP + sbi->cache_strategy = EROFS_ZIP_CACHE_READAROUND; + sbi->max_sync_decompress_pages = 3; +#endif +#ifdef CONFIG_EROFS_FS_XATTR + set_opt(sbi, XATTR_USER); +#endif +#ifdef CONFIG_EROFS_FS_POSIX_ACL + set_opt(sbi, POSIX_ACL); +#endif +} + +enum { + Opt_user_xattr, + Opt_nouser_xattr, + Opt_acl, + Opt_noacl, + Opt_cache_strategy, + Opt_err +}; + +static match_table_t erofs_tokens = { + {Opt_user_xattr, "user_xattr"}, + {Opt_nouser_xattr, "nouser_xattr"}, + {Opt_acl, "acl"}, + {Opt_noacl, "noacl"}, + {Opt_cache_strategy, "cache_strategy=%s"}, + {Opt_err, NULL} +}; + +static int erofs_parse_options(struct super_block *sb, char *options) +{ + substring_t args[MAX_OPT_ARGS]; + char *p; + int err; + + if (!options) + return 0; + + while ((p = strsep(&options, ","))) { + int token; + + if (!*p) + continue; + + args[0].to = args[0].from = NULL; + token = match_token(p, erofs_tokens, args); + + switch (token) { +#ifdef CONFIG_EROFS_FS_XATTR + case Opt_user_xattr: + set_opt(EROFS_SB(sb), XATTR_USER); + break; + case Opt_nouser_xattr: + clear_opt(EROFS_SB(sb), XATTR_USER); + break; +#else + case Opt_user_xattr: + erofs_info(sb, "user_xattr options not supported"); + break; + case Opt_nouser_xattr: + erofs_info(sb, "nouser_xattr options not supported"); + break; +#endif +#ifdef CONFIG_EROFS_FS_POSIX_ACL + case Opt_acl: + set_opt(EROFS_SB(sb), POSIX_ACL); + break; + case Opt_noacl: + clear_opt(EROFS_SB(sb), POSIX_ACL); + break; +#else + case Opt_acl: + erofs_info(sb, "acl options not supported"); + break; + case Opt_noacl: + erofs_info(sb, "noacl options not supported"); + break; +#endif + case Opt_cache_strategy: + err = erofs_build_cache_strategy(sb, args); + if (err) + return err; + break; + default: + erofs_err(sb, "Unrecognized mount option \"%s\" or missing value", p); + return -EINVAL; + } + } + return 0; +} + +#ifdef CONFIG_EROFS_FS_ZIP +static const struct address_space_operations managed_cache_aops; + +static int erofs_managed_cache_releasepage(struct page *page, gfp_t gfp_mask) +{ + int ret = 1; /* 0 - busy */ + struct address_space *const mapping = page->mapping; + + DBG_BUGON(!PageLocked(page)); + DBG_BUGON(mapping->a_ops != &managed_cache_aops); + + if (PagePrivate(page)) + ret = erofs_try_to_free_cached_page(mapping, page); + + return ret; +} + +static void erofs_managed_cache_invalidatepage(struct page *page, + unsigned int offset, + unsigned int length) +{ + const unsigned int stop = length + offset; + + DBG_BUGON(!PageLocked(page)); + + /* Check for potential overflow in debug mode */ + DBG_BUGON(stop > PAGE_SIZE || stop < length); + + if (offset == 0 && stop == PAGE_SIZE) + while (!erofs_managed_cache_releasepage(page, GFP_NOFS)) + cond_resched(); +} + +static const struct address_space_operations managed_cache_aops = { + .releasepage = erofs_managed_cache_releasepage, + .invalidatepage = erofs_managed_cache_invalidatepage, +}; + +static int erofs_init_managed_cache(struct super_block *sb) +{ + struct erofs_sb_info *const sbi = EROFS_SB(sb); + struct inode *const inode = new_inode(sb); + + if (!inode) + return -ENOMEM; + + set_nlink(inode, 1); + inode->i_size = OFFSET_MAX; + + inode->i_mapping->a_ops = &managed_cache_aops; + mapping_set_gfp_mask(inode->i_mapping, + GFP_NOFS | __GFP_HIGHMEM | __GFP_MOVABLE); + sbi->managed_cache = inode; + return 0; +} +#else +static int erofs_init_managed_cache(struct super_block *sb) { return 0; } +#endif + +static int erofs_fill_super(struct super_block *sb, void *data, int silent) +{ + struct inode *inode; + struct erofs_sb_info *sbi; + int err; + + sb->s_magic = EROFS_SUPER_MAGIC; + + if (!sb_set_blocksize(sb, EROFS_BLKSIZ)) { + erofs_err(sb, "failed to set erofs blksize"); + return -EINVAL; + } + + sbi = kzalloc(sizeof(*sbi), GFP_KERNEL); + if (!sbi) + return -ENOMEM; + + sb->s_fs_info = sbi; + err = erofs_read_superblock(sb); + if (err) + return err; + + sb->s_flags |= SB_RDONLY | SB_NOATIME; + sb->s_maxbytes = MAX_LFS_FILESIZE; + sb->s_time_gran = 1; + + sb->s_op = &erofs_sops; + +#ifdef CONFIG_EROFS_FS_XATTR + sb->s_xattr = erofs_xattr_handlers; +#endif + /* set erofs default mount options */ + erofs_default_options(sbi); + + err = erofs_parse_options(sb, data); + if (err) + return err; + + if (test_opt(sbi, POSIX_ACL)) + sb->s_flags |= SB_POSIXACL; + else + sb->s_flags &= ~SB_POSIXACL; + +#ifdef CONFIG_EROFS_FS_ZIP + INIT_RADIX_TREE(&sbi->workstn_tree, GFP_ATOMIC); +#endif + + /* get the root inode */ + inode = erofs_iget(sb, ROOT_NID(sbi), true); + if (IS_ERR(inode)) + return PTR_ERR(inode); + + if (!S_ISDIR(inode->i_mode)) { + erofs_err(sb, "rootino(nid %llu) is not a directory(i_mode %o)", + ROOT_NID(sbi), inode->i_mode); + iput(inode); + return -EINVAL; + } + + sb->s_root = d_make_root(inode); + if (!sb->s_root) + return -ENOMEM; + + erofs_shrinker_register(sb); + /* sb->s_umount is already locked, SB_ACTIVE and SB_BORN are not set */ + err = erofs_init_managed_cache(sb); + if (err) + return err; + + erofs_info(sb, "mounted with opts: %s, root inode @ nid %llu.", + (char *)data, ROOT_NID(sbi)); + return 0; +} + +static struct dentry *erofs_mount(struct file_system_type *fs_type, int flags, + const char *dev_name, void *data) +{ + return mount_bdev(fs_type, flags, dev_name, data, erofs_fill_super); +} + +/* + * could be triggered after deactivate_locked_super() + * is called, thus including umount and failed to initialize. + */ +static void erofs_kill_sb(struct super_block *sb) +{ + struct erofs_sb_info *sbi; + + WARN_ON(sb->s_magic != EROFS_SUPER_MAGIC); + + kill_block_super(sb); + + sbi = EROFS_SB(sb); + if (!sbi) + return; + kfree(sbi); + sb->s_fs_info = NULL; +} + +/* called when ->s_root is non-NULL */ +static void erofs_put_super(struct super_block *sb) +{ + struct erofs_sb_info *const sbi = EROFS_SB(sb); + + DBG_BUGON(!sbi); + + erofs_shrinker_unregister(sb); +#ifdef CONFIG_EROFS_FS_ZIP + iput(sbi->managed_cache); + sbi->managed_cache = NULL; +#endif +} + +static struct file_system_type erofs_fs_type = { + .owner = THIS_MODULE, + .name = "erofs", + .mount = erofs_mount, + .kill_sb = erofs_kill_sb, + .fs_flags = FS_REQUIRES_DEV, +}; +MODULE_ALIAS_FS("erofs"); + +static int __init erofs_module_init(void) +{ + int err; + + erofs_check_ondisk_layout_definitions(); + + erofs_inode_cachep = kmem_cache_create("erofs_inode", + sizeof(struct erofs_inode), 0, + SLAB_RECLAIM_ACCOUNT, + erofs_inode_init_once); + if (!erofs_inode_cachep) { + err = -ENOMEM; + goto icache_err; + } + + err = erofs_init_shrinker(); + if (err) + goto shrinker_err; + + err = z_erofs_init_zip_subsystem(); + if (err) + goto zip_err; + + err = register_filesystem(&erofs_fs_type); + if (err) + goto fs_err; + + return 0; + +fs_err: + z_erofs_exit_zip_subsystem(); +zip_err: + erofs_exit_shrinker(); +shrinker_err: + kmem_cache_destroy(erofs_inode_cachep); +icache_err: + return err; +} + +static void __exit erofs_module_exit(void) +{ + unregister_filesystem(&erofs_fs_type); + z_erofs_exit_zip_subsystem(); + erofs_exit_shrinker(); + + /* Ensure all RCU free inodes are safe before cache is destroyed. */ + rcu_barrier(); + kmem_cache_destroy(erofs_inode_cachep); +} + +/* get filesystem statistics */ +static int erofs_statfs(struct dentry *dentry, struct kstatfs *buf) +{ + struct super_block *sb = dentry->d_sb; + struct erofs_sb_info *sbi = EROFS_SB(sb); + u64 id = huge_encode_dev(sb->s_bdev->bd_dev); + + buf->f_type = sb->s_magic; + buf->f_bsize = EROFS_BLKSIZ; + buf->f_blocks = sbi->blocks; + buf->f_bfree = buf->f_bavail = 0; + + buf->f_files = ULLONG_MAX; + buf->f_ffree = ULLONG_MAX - sbi->inos; + + buf->f_namelen = EROFS_NAME_LEN; + + buf->f_fsid.val[0] = (u32)id; + buf->f_fsid.val[1] = (u32)(id >> 32); + return 0; +} + +static int erofs_show_options(struct seq_file *seq, struct dentry *root) +{ + struct erofs_sb_info *sbi __maybe_unused = EROFS_SB(root->d_sb); + +#ifdef CONFIG_EROFS_FS_XATTR + if (test_opt(sbi, XATTR_USER)) + seq_puts(seq, ",user_xattr"); + else + seq_puts(seq, ",nouser_xattr"); +#endif +#ifdef CONFIG_EROFS_FS_POSIX_ACL + if (test_opt(sbi, POSIX_ACL)) + seq_puts(seq, ",acl"); + else + seq_puts(seq, ",noacl"); +#endif +#ifdef CONFIG_EROFS_FS_ZIP + if (sbi->cache_strategy == EROFS_ZIP_CACHE_DISABLED) { + seq_puts(seq, ",cache_strategy=disabled"); + } else if (sbi->cache_strategy == EROFS_ZIP_CACHE_READAHEAD) { + seq_puts(seq, ",cache_strategy=readahead"); + } else if (sbi->cache_strategy == EROFS_ZIP_CACHE_READAROUND) { + seq_puts(seq, ",cache_strategy=readaround"); + } else { + seq_puts(seq, ",cache_strategy=(unknown)"); + DBG_BUGON(1); + } +#endif + return 0; +} + +static int erofs_remount(struct super_block *sb, int *flags, char *data) +{ + struct erofs_sb_info *sbi = EROFS_SB(sb); + unsigned int org_mnt_opt = sbi->mount_opt; + int err; + + DBG_BUGON(!sb_rdonly(sb)); + err = erofs_parse_options(sb, data); + if (err) + goto out; + + if (test_opt(sbi, POSIX_ACL)) + sb->s_flags |= SB_POSIXACL; + else + sb->s_flags &= ~SB_POSIXACL; + + *flags |= SB_RDONLY; + return 0; +out: + sbi->mount_opt = org_mnt_opt; + return err; +} + +const struct super_operations erofs_sops = { + .put_super = erofs_put_super, + .alloc_inode = erofs_alloc_inode, + .free_inode = erofs_free_inode, + .statfs = erofs_statfs, + .show_options = erofs_show_options, + .remount_fs = erofs_remount, +}; + +module_init(erofs_module_init); +module_exit(erofs_module_exit); + +MODULE_DESCRIPTION("Enhanced ROM File System"); +MODULE_AUTHOR("Gao Xiang, Chao Yu, Miao Xie, CONSUMER BG, HUAWEI Inc."); +MODULE_LICENSE("GPL"); + |